The multipurpose composite flywheel

The twin disk composite flywheel shows that the techniques that were developed at Rocketdyne to successfully design, fabricate, and test high-speed rotating machinery (turbopumps) for rocket engines could be used to develop advanced flywheels. This flywheel not only demonstrates that successful mating of metal flywheel characteristics (high torque and ruggedness) and composite flywheel characteristics (lightweight and high energy density) can be achieved, but the unique design lends itself to easy adaptation to other configurations

Individual Insurance: Health Insurers Try to Tap Potential Market Growth

Examines the challenges the current individual health insurance market poses for insurers and consumers, the market's growth potential, market and regulatory conditions across states, and trends in marketing strategies. Considers policy implications

International Courts as Agents of Legal Change: Evidence from LGBT Rights in Europe

Do international court judgments influence the behavior of actors other than the parties to a dispute? Are international courts agents of policy change or do their judgments merely reflect evolving social and political trends? The authors develop a theory that specifies the conditions under which international courts can use their interpretive discretion to have system-wide effects. The authors examine the theory in the context of European Court of Human Rights (ECtHR) rulings on lesbian, gay, bisexual and transgender (LGBT) issues by creating a new dataset that matches these rulings with laws in all Council of Europe (CoE) member states. The authors also collect data on LGBT policies unaffected by ECtHR judgments to control for the confounding effect of evolving trends in national policies. The authors find that ECtHR judgments against one country substantially increase the probability of national-level policy change across Europe. The marginal effects of the judgments are especially high where public acceptance of sexual minorities is low, but where national courts can rely on ECtHR precedents to invalidate domestic laws or where the government in power is not ideologically opposed to LGBT equality. The authors conclude by exploring the implications of our findings for other international courts

Performance of Compressor of XJ-41-V Turbojet Engine VI - Analysis of Compressor Flow Choking

An extended analysis was made of the previously reported performance investigation of the original compressor from the XJ-41-v turbojet engine and a similar compressor revised a to obtain a 33-percent increase in the geometric passage area at the vaned-collector entrance. This analysis was based on the concept of the vaned-collector entrance as the throat section of a nozzle. Because of nonuniform air distribution at the vaned-collector entrance, approximately 90 percent of the available flow area was utilized in the original compressor and 94percent in the revised com$ressor. The increase in maximum weight flow obtained with the revised compressor was disproportionate to the increased effective critical throat area because. the air density at the revised vaned-collector entrance for maximum flow was lower than that obtained in the original compressor. This reduction in density resulted from the large pressure losses near the impeller inlet of the revised compressor, which is indicative of impending flow choking in the impeller, The.calculated maximum corrected weight-flow capacity of a compressor consisting of the revised vaneless diffuser and vaned collector with a theoretical impeller that combined peak impeller pressure ratio and peak impeller efficiency at the . maximum flow point would be 112 pounds per second for an equivalent impeller speed of 11,500 rpm

Performance of Compressor of XJ-41-V Turbojet Engine

An investigation of the XJ-41-V turbojet-engine compressor was conducted to determine the performance of the compressor and to obtain fundamental information on the aerodynamic problems associated with large centrifugal-type compressors. The results of the research conducted on the original compressor indicated the compressor would not meet the desired engine-design air-flow requirements because of an air-flow restriction in the vaned collector. The compressor air-flow choking point occurred near the entrance to the vaned-collector passage and was instigated by a poor mass-flow distribution at the vane entrance and from relatively large negative angles of attack of the air stream along the entrance edges of the vanes at the outer passage wall and large positive angles of attack at the inner passage wall. As a result of the analysis, a design change of the vaned collector entrance is recommended for improving the maximum flow capacity of the compressor

Sofic-Dyck shifts

We define the class of sofic-Dyck shifts which extends the class of Markov-Dyck shifts introduced by Inoue, Krieger and Matsumoto. Sofic-Dyck shifts are shifts of sequences whose finite factors form unambiguous context-free languages. We show that they correspond exactly to the class of shifts of sequences whose sets of factors are visibly pushdown languages. We give an expression of the zeta function of a sofic-Dyck shift

TurbuStat: Turbulence Statistics in Python

We present TurbuStat (v1.0): a Python package for computing turbulence statistics in spectral-line data cubes. TurbuStat includes implementations of fourteen methods for recovering turbulent properties from observational data. Additional features of the software include: distance metrics for comparing two data sets; a segmented linear model for fitting lines with a break-point; a two-dimensional elliptical power-law model; multi-core fast-fourier-transform support; a suite for producing simulated observations of fractional Brownian Motion fields, including two-dimensional images and optically-thin HI data cubes; and functions for creating realistic world coordinate system information for synthetic observations. This paper summarizes the TurbuStat package and provides representative examples using several different methods. TurbuStat is an open-source package and we welcome community feedback and contributions.Comment: Accepted in AJ. 21 pages, 8 figure